There are several so-called “integrated actuators” which contain the elements of a valve, fluid power cylinder, and even a sensor, but these prior art products are not in fact fully integrated. Examples include products offered by Enfield Technologies, assignee of the present invention, as well as those from other vendors such as Norgren or Allen Air.
There are also examples of vendors that provide some or all of these elements as individual items or in various forms of sub-assembly which can be assembled as a construction of separate components, but none are unified into a single product and offered as such. Examples include Bimba, Dyval (Parker Hannifin), Festo, Hoerbiger-Origa, and Si-Plan Electronics, Ltd., as well as in research laboratories such as at Vanderbilt, UC Berkeley, and McMaster to name a few academic institutions who have constructed such systems.
However, none provide for fully integrated on-board closed-loop signal processing and control. The commercial need for such a fully integrated product has not been recognized by others working in the art, and the technical challenges to constructing such a device have been formidable. The present invention has overcome these technical challenges.
Industry standard practice has been to configure systems with control systems and power drivers physically separate from actuators. This holds true for both fluid power (hydraulic and pneumatic) systems as well as electromechanical systems (such as linear motors and rotary motor/leadscrew drives).
The challenges have included: the number of valve and valve control devices required to create such a system, and coordination of those devices, control electronics small enough to be placed on-board the actuator itself, and schemes to provide command signals without degradation.